CN104724678A - Method for fluidized catalytic decomposition of gypsum - Google Patents

Abstract

The invention discloses a method for fluidized catalytic decomposition of gypsum. The gypsum is uniformly mixed with a metal oxide molecular sieve catalyst and added to a fluidized reactor. Sulfur gas enters from the bottom of the fluidized reactor and contacts with solid materials to react and decompose the gypsum. The solid phase obtained by the reaction is washed with steam, and the solid phase after washing is a metal oxide molecular sieve catalyst, and is recycled after being dried. The washed gas phase was condensed to obtain _a Ca(OH) suspension for the preparation of calcium salts. The uncondensed gas phase can be used alone or with _SO2 in the gas phase product after the gypsum decomposition reaction to produce sulfur according to the Claus reaction, which can be recycled as a reducing agent. The gas phase obtained from the gypsum decomposition reaction is dedusted, cooled, separated to prepare insoluble sulfur, and the soluble sulfur is recycled as a reducing agent. The remaining gas phase can be combined with H ₂ S to produce sulfur and then recycled as a reducing agent, or to produce sulfuric acid. The invention has the advantages of low energy consumption for decomposition of gypsum, fast decomposition rate, high added value of the product, and advanced environmental protection process.

Description

A method for fluidized catalytic decomposition of gypsum

technical field

The invention relates to the technical field of utilization of gypsum resources, in particular to a method for fluidized catalytic decomposition of gypsum.

Background technique

my country has abundant natural gypsum resources and various industrial by-product gypsum resources piled up in huge quantities. At the same time, my country is facing the resource dilemma of lack of sulfur resources and calcium oxide resources mainly using limestone as raw material. my country's sulfur resource industry, especially the production of sulfuric acid, relies heavily on imported sulfur from abroad, making the development of the entire industry subject to others and full of risks. However, obtaining calcium oxide resources by calcining limestone also emits a large amount of greenhouse gas carbon dioxide, which seriously deviates from the current environmental protection trend of energy conservation and emission reduction. Decomposing gypsum to obtain sulfur and calcium resources respectively can solve the problems faced by the above two resource industries.

Among such gypsum decomposition technologies, the most typical one is the process technology of decomposing gypsum to prepare sulfuric acid co-production cement. Especially when the industrial by-product gypsum such as phosphogypsum is used as the raw material, the sulfur element can be recycled through the migration of phosphogypsum-sulfuric acid-phosphoric acid. However, the current gypsum decomposition technology still has the following problems: high energy consumption for gypsum decomposition, slow decomposition rate, low added value of products, environmental pollution, and backward technology. In response to this situation, some new technical solutions have been proposed in recent years.

Chinese invention patent ZL200910216325.2 discloses a method for reducing and decomposing phosphogypsum by sulfur, which is characterized in that the phosphogypsum is first put into a reactor and heated to 500-900°C for 10-30 minutes under an inert atmosphere, and then Feed in gaseous sulfur with a molar fraction of 10-50% and phosphogypsum for reduction reaction for 1-2 hours, grind the obtained calcium sulfide block and then mix it with phosphogypsum at a molar ratio of 1-1.5:3. Roasting at 1000-1400°C for 0.5-3 hours in an oxidizing atmosphere, the CaO in the obtained solid slag is used as cement clinker for cement production, and the generated tail gas SO ₂ is used as raw material gas for sulfuric acid production.

Chinese invention patent ZL201010223874.5 discloses a method for vibrating fluidized decomposition of phosphogypsum. It is characterized in that the composite admixture and the pretreated phosphogypsum are mixed evenly according to the mass ratio of 1:7, and sent to the uniform fluidized decomposition furnace outside the kiln, and the temperature is raised to 850-1100 °C under the protection of Ar atmosphere, and then the temperature is 5-100 °C. The flow rate of 50ml/min is passed into CO, and the volume flow ratio of CO and Ar is 1:(2~19), the temperature is controlled at 850~1100°C, and the vibration energy loading device is started for reduction and decomposition.

Chinese invention patent application CN103864024A discloses a method for catalytically decomposing phosphogypsum. The technical solution is: mix phosphogypsum and carbonized rice husk uniformly in a mass ratio (20-1):1 to prepare a mixture. Then put the mixture into a tube furnace, and carry out a catalytic decomposition reaction at 600-900°C. The reaction time is 60-180min. The sulfur dioxide gas obtained by the reaction is directly produced into sulfuric acid, and the solid product obtained by the reaction is active lime. , or calcium silicate, or active lime and calcium silicate.

The above-mentioned technical solutions have made certain contributions in solving the problems of high decomposition energy consumption, slow decomposition rate, environmental pollution, and backward technology of gypsum decomposition technology, but they are not comprehensive, and all of them have low added value of products, which cannot make the technical solutions obtain good economic benefits. Shortcomings.

Contents of the invention

The purpose of the present invention is to propose a new method for gypsum decomposition that can comprehensively solve the various shortcomings of the above-mentioned gypsum decomposition technology.

The present invention adopts following technical scheme:

The concrete steps of the method for fluidized catalytic decomposition of gypsum of the present invention are as follows:

(1), the powdery gypsum raw material and the metal oxide molecular sieve catalyst particles are mixed evenly according to the mass ratio (1-30): 1, and then added to the fluidized reactor;

(2), the sulfur gas after sulfur gasification of the reducing agent enters from the bottom of the fluidized reactor according to the mass ratio (2 to 10): 1 with the gypsum powder, and the gas phase molar fraction is 10% to 100%. During material contact, the gypsum is decomposed at 480°C-700°C, the residence time of the material is 1-60min, and the decomposition rate of gypsum is 60%-100%.

(3), the solid phase (calcium sulfide mass fraction is 40%～100% powder and catalyst particle) that fluidized catalytic decomposition reaction obtains carries out steam washing, and the solid phase after washing is metal oxide molecular sieve catalyst, at 120 ℃～200℃ and return to step (1) for recycling after drying. The gas phase is condensed first to obtain a suspension with a mass fraction of calcium hydroxide of 20% to 60%, and then reacts with carbon dioxide, nitric acid, phosphoric acid, hydrochloric acid, etc. to produce calcium carbonate, calcium nitrate, calcium hydrogen phosphate, calcium chloride, etc. Salt. The uncondensed gas phase (with a hydrogen sulfide mole fraction of 80% to 100%) can be used alone or with the sulfur dioxide in the gas phase product after the fluidized catalytic decomposition reaction to produce sulfur by Claus reaction, and then returned to the system for recycling as a reducing agent .

(4) The gas phase at 480°C to 700°C (the molar fraction of sulfur dioxide is 6% to 20%, and the molar fraction of sulfur gas is 5% to 80%) obtained from the fluidized catalytic decomposition reaction is dedusted and cooled to 120°C to At 150°C, the gaseous sulfur is quenched into liquid sulfur, and insoluble sulfur with a purity ≥ 98% is prepared by separation, while the soluble sulfur is returned to the system as a reducing agent for recycling. The remaining gas phase (mole fraction of sulfur dioxide is 5% to 30%) is then washed with the solid phase product to obtain hydrogen sulfide through Claus reaction to produce sulfur and return to the system as a reducing agent for recycling, or to produce sulfuric acid.

In step (1), the gypsum raw material is one or more of natural gypsum, anhydrite, phosphogypsum, desulfurized gypsum, fluorine gypsum, citrate gypsum, nickel gypsum, salt gypsum or titanium dioxide by-product gypsum .

In step (1), the metal oxide component contained in the metal oxide molecular sieve catalyst is the oxide of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, aluminum, gallium or germanium one or more of.

The final product is insoluble sulfur, sulfuric acid and at least one of these calcium salts of calcium carbonate, calcium nitrate, calcium hydrogen phosphate and calcium chloride.

The method for decomposing gypsum by fluidization catalysis of the present invention has the advantages of low decomposition energy consumption, fast decomposition rate, high added value of products, and advanced environmental protection technology.

Compared with the prior art, the present invention has the following remarkable features and beneficial effects:

1. Using the fluidized catalytic decomposition method, by strengthening the mass transfer of the reaction and reducing the energy barrier of the reaction, the effect of significantly reducing the energy consumption of the reaction and accelerating the reaction rate is achieved.

2. Fluidization and catalysis are coupled with each other in this method. Sulfur is both a reducing agent and a fluidization medium. The catalyst can not only play a catalytic role but also effectively improve the fluidization performance of gypsum particles, which cannot be realized by the prior art.

3. By preparing products such as high value-added insoluble sulfur and fine calcium salt, the value of the product is improved, so that the method has strong technical and economic competitiveness.

4. Compared with the existing technical solutions, this method not only does not emit greenhouse gases such as carbon dioxide in the process of decomposing gypsum, but also absorbs and utilizes carbon dioxide, and has excellent environmental protection characteristics of zero carbon emissions.

5. In this method, the catalyst can be reused, the intermediate product can be used to prepare and recover the raw material sulfur, and the product sulfuric acid can realize the industrial chain cycle of sulfuric acid → gypsum → sulfuric acid. Therefore, compared with the existing scheme, it has outstanding circular economy effects.

Description of drawings

Fig. 1 is a process flow chart of the method for fluidized catalytic decomposition of gypsum of the present invention.

Detailed ways

The present invention is specifically described below through the examples, it is necessary to point out that the present examples are only used to further illustrate the present invention, and can not be interpreted as limiting the protection scope of the present invention, those skilled in the art according to the above-mentioned present invention Contents Some non-essential improvements and adjustments made to the present invention should still belong to the protection scope of the present invention.

Example 1

(1), powdered natural gypsum or anhydrite raw material and iron or scandium oxide molecular sieve catalyst particles are mixed evenly according to the mass ratio of 1:1, and then added to the fluidized reactor;

(2) Sulfur gas after sulfur gasification of the reducing agent enters from the bottom of the fluidized reactor at a mass ratio of 2:1 to gypsum powder and a mole fraction of the gas phase of 10%, and contacts with the material in (1), at 550°C To decompose gypsum, the residence time of the material is 1min, and the decomposition rate of gypsum is 60%.

(3), the solid phase obtained by the fluidized catalytic decomposition reaction (calcium sulfide mass fraction is 40% powder and catalyst particles) is steam washed, and the solid phase after washing is a metal oxide molecular sieve catalyst, after drying at 120 ° C Return to step (1) for recycling. The gas phase is first condensed to obtain a suspension with a mass fraction of calcium hydroxide of 20%, which can be reacted with carbon dioxide, nitric acid, phosphoric acid, hydrochloric acid, etc. to produce calcium salts such as calcium carbonate, calcium nitrate, calcium hydrogen phosphate, and calcium chloride. The uncondensed gas phase (containing hydrogen sulfide with a mole fraction of 80%) can be used alone or with sulfur dioxide in the gas phase product after the fluidized catalytic decomposition reaction to produce sulfur by Claus reaction, and then returned to the system for recycling as a reducing agent.

(4), the 550 ℃ gaseous phase (sulfur dioxide molar fraction is 6%, sulfur gas molar fraction is 80%) that the fluidized catalytic decomposition reaction obtains is through dedusting, is cooled to 150 ℃, makes gaseous sulfur quench to be liquid sulfur, through Separation and preparation of insoluble sulfur with a purity ≥ 98%, while soluble sulfur is returned to the system as a reducing agent for recycling. The remaining gas phase (the molar fraction of sulfur dioxide is 30%) can be partially reacted with the hydrogen sulfide obtained after washing the solid phase product to produce sulfur and then returned to the system for recycling as a reducing agent, and the other part can be used to produce sulfuric acid.

Example 2

(1), powdery desulfurization gypsum or salt gypsum raw material and titanium or manganese oxide molecular sieve catalyst particles are mixed evenly according to the mass ratio of 10:1, and then added to the fluidized reactor;

(2) Sulfur gas after gasification of sulfur as a reducing agent enters from the bottom of the fluidized reactor at a mass ratio of 3:1 to gypsum powder and a mole fraction of the gas phase of 40%, and contacts with the material in (1), at 600°C Decompose gypsum, the material residence time is 10min, and the gypsum decomposition rate is 80%.

(3), the solid phase obtained by the fluidized catalytic decomposition reaction (calcium sulfide mass fraction is 70% powder and catalyst particles) is steam washed, and the solid phase after washing is a metal oxide molecular sieve catalyst, after drying at 150 ° C Return to step (1) for recycling. The gas phase is first condensed to obtain a suspension with a mass fraction of calcium hydroxide of 30%, which can be reacted with carbon dioxide, nitric acid, phosphoric acid, hydrochloric acid, etc. to produce calcium carbonate, calcium nitrate, calcium hydrogen phosphate, calcium chloride and other calcium salts. The uncondensed gas phase (containing hydrogen sulfide with a mole fraction of 85%) can be used alone or with sulfur dioxide in the gas phase product after the fluidized catalytic decomposition reaction to produce sulfur by Claus reaction, and then returned to the system for recycling as a reducing agent.

(4), the 600 DEG C gaseous phase (sulfur dioxide molar fraction is 8%, sulfur gas molar fraction is 60%) that the fluidized catalytic decomposition reaction obtains is through dedusting, is cooled to 130 DEG C, makes gaseous state sulfur be quenched into liquid sulfur, through Separation and preparation of insoluble sulfur with a purity ≥ 99%, while soluble sulfur is returned to the system as a reducing agent for recycling. The remaining gas phase (the molar fraction of sulfur dioxide is 15%) can be partially reacted with the hydrogen sulfide obtained after washing the solid phase product to produce sulfur and then returned to the system for recycling as a reducing agent, and the other part can be used to produce sulfuric acid.

Example 3

(1), powdery titanium dioxide by-product gypsum raw material and vanadium or chromium oxide molecular sieve catalyst particles are mixed evenly according to the mass ratio of 5:1, and added to the fluidized reactor;

(2) Sulfur gas after sulfur gasification of the reducing agent enters from the bottom of the fluidized reactor at a mass ratio of 6:1 to gypsum powder and a mole fraction of the gas phase of 50%, and contacts with the material in (1), at 620°C Decompose gypsum, the material residence time is 20min, and the gypsum decomposition rate is 90%.

(3), the solid phase obtained by the fluidized catalytic decomposition reaction (calcium sulfide mass fraction is 95% powder and catalyst particles) is steam washed, and the solid phase after washing is a metal oxide molecular sieve catalyst, after drying at 180 ° C Return to step (1) for recycling. The gas phase is first condensed to obtain a suspension with a mass fraction of calcium hydroxide of 45%, which can be reacted with carbon dioxide, nitric acid, phosphoric acid, hydrochloric acid, etc. to produce calcium salts such as calcium carbonate, calcium nitrate, calcium hydrogen phosphate, and calcium chloride. The uncondensed gas phase (with a hydrogen sulfide molar fraction of 95%) can be used alone or with the sulfur dioxide in the gas phase product after the fluidized catalytic decomposition reaction to produce sulfur by Claus reaction, and then returned to the system for recycling as a reducing agent.

(4), the gas phase of 620 DEG C obtained by fluidized catalytic decomposition reaction (the molar fraction of sulfur dioxide is 12%, the molar fraction of sulfur gas is 55%) is dedusted, cooled to 145 DEG C, the gaseous sulfur is quenched into liquid sulfur, and the Separation and preparation of insoluble sulfur with a purity ≥ 98.5%, while soluble sulfur is returned to the system as a reducing agent for recycling. The remaining gas phase (the molar fraction of sulfur dioxide is 10%) can be partially reacted with the hydrogen sulfide obtained after washing the solid phase product to produce sulfur and then returned to the system for recycling as a reducing agent, and the other part can be used to produce sulfuric acid.

Example 4

(1), powdery phosphogypsum raw material and iron or aluminum oxide molecular sieve catalyst particles are mixed evenly according to the mass ratio of 20:1, and then added to the fluidized reactor;

(2) Sulfur gas after sulfur gasification of the reducing agent enters from the bottom of the fluidized reactor at a mass ratio of 7:1 to gypsum powder and a gas phase molar fraction of 30%, and contacts with the material in (1), at 650°C To decompose gypsum, the material residence time is 5 minutes, and the gypsum decomposition rate is 100%.

(3), the solid phase (calcium sulfide mass fraction is 100% powder and catalyst particles) obtained by fluidized catalytic decomposition reaction is steam washed, and the solid phase after washing is a metal oxide molecular sieve catalyst, after drying at 200 ° C Return to step (1) for recycling. The gas phase is first condensed to obtain a suspension with a mass fraction of calcium hydroxide of 60%, which can be reacted with carbon dioxide, nitric acid, phosphoric acid, hydrochloric acid, etc. to produce calcium salts such as calcium carbonate, calcium nitrate, calcium hydrogen phosphate, and calcium chloride. The uncondensed gas phase (100% mole fraction of hydrogen sulfide) can be used alone or with the sulfur dioxide in the gas phase product after the fluidized catalytic decomposition reaction to produce sulfur by Claus reaction, and then returned to the system for recycling as a reducing agent.

(4), the 650 DEG C gaseous phase (sulfur dioxide molar fraction is 20%, sulfur gas molar fraction is 50%) that the fluidized catalytic decomposition reaction obtains is through dedusting, is cooled to 120 DEG C, makes gaseous sulfur quick-cooling is liquid sulfur, through Separation and preparation of insoluble sulfur with a purity ≥ 99.5%, while soluble sulfur is returned to the system as a reducing agent for recycling. The remaining gas phase (the molar fraction of sulfur dioxide is 5%) can be partially reacted with the hydrogen sulfide obtained after washing the solid phase product to produce sulfur and then returned to the system for recycling as a reducing agent, and the other part can be used to produce sulfuric acid.

Example 5

(1), powdery citrate gypsum raw material and cobalt or copper oxide molecular sieve catalyst particles are mixed evenly according to mass ratio 15:1, join in the fluidized reactor;

(2) The sulfur gas after sulfur gasification of the reducing agent enters from the bottom of the fluidized reactor at a mass ratio of 10:1 to gypsum powder and a gas phase molar fraction of 70%, and contacts with the material in (1), at 700°C To decompose gypsum, the material residence time is 15 minutes, and the gypsum decomposition rate is 95%.

(3), the solid phase obtained by the fluidized catalytic decomposition reaction (calcium sulfide mass fraction is 98% powder and catalyst particles) is steam washed, and the solid phase after washing is a metal oxide molecular sieve catalyst, after drying at 150 ° C Return to step (1) for recycling. The gas phase is first condensed to obtain a suspension with a mass fraction of calcium hydroxide of 50%, which can be reacted with carbon dioxide, nitric acid, phosphoric acid, hydrochloric acid, etc. to produce calcium salts such as calcium carbonate, calcium nitrate, calcium hydrogen phosphate, and calcium chloride. The uncondensed gas phase (with a hydrogen sulfide molar fraction of 90%) can be used alone or with the sulfur dioxide in the gas phase product after the fluidized catalytic decomposition reaction to produce sulfur by Claus reaction, and then returned to the system for recycling as a reducing agent.

(4), the 700 DEG C gaseous phase (sulfur dioxide molar fraction is 16%, sulfur gas molar fraction is 58%) that the fluidized catalytic decomposition reaction obtains is through dedusting, is cooled to 125 DEG C, makes gaseous sulfur quench to be liquid sulfur, through Separation and preparation of insoluble sulfur with a purity ≥ 99%, while soluble sulfur is returned to the system as a reducing agent for recycling. The remaining gas phase (the molar fraction of sulfur dioxide is 12%) can be partially reacted with the hydrogen sulfide obtained after washing the solid phase product to produce sulfur and then returned to the system for recycling as a reducing agent, and the other part can be used to produce sulfuric acid.

Example 6

(1), powdery nickel gypsum raw material and nickel or zinc oxide molecular sieve catalyst particles are mixed evenly according to the mass ratio of 30:1, and then added to the fluidized reactor;

(2) The sulfur gas after sulfur gasification of the reducing agent enters from the bottom of the fluidized reactor according to the mass ratio of 4:1 to gypsum powder, and the molar fraction of the gas phase is 100%, and contacts with the material in (1), at 480°C Decompose gypsum, the material residence time is 60min, and the gypsum decomposition rate is 90%.

(3), the solid phase obtained by the fluidized catalytic decomposition reaction (calcium sulfide mass fraction is 95% powder and catalyst particles) is steam washed, and the solid phase after washing is a metal oxide molecular sieve catalyst, after drying at 120 ° C Return to step (1) for recycling. The gas phase is first condensed to obtain a suspension with a mass fraction of calcium hydroxide of 45%, which can be reacted with carbon dioxide, nitric acid, phosphoric acid, hydrochloric acid, etc. to produce calcium salts such as calcium carbonate, calcium nitrate, calcium hydrogen phosphate, and calcium chloride. The uncondensed gas phase (with a hydrogen sulfide molar fraction of 98%) can be used alone or with the sulfur dioxide in the gas phase product after the fluidized catalytic decomposition reaction to produce sulfur by Claus reaction, and then returned to the system for recycling as a reducing agent.

(4), the 480 DEG C gaseous phase (sulfur dioxide molar fraction is 12%, sulfur gas molar fraction is 55%) that the fluidized catalytic decomposition reaction obtains is through dedusting, is cooled to 140 DEG C, makes gaseous sulfur quick-cooling is liquid sulfur, through Separation and preparation of insoluble sulfur with a purity ≥ 98%, while soluble sulfur is returned to the system as a reducing agent for recycling. The remaining gas phase (the molar fraction of sulfur dioxide is 10%) can be partially reacted with the hydrogen sulfide obtained after washing the solid phase product to produce sulfur and then returned to the system for recycling as a reducing agent, and the other part can be used to produce sulfuric acid.

Example 7

(1), powdery fluorogypsum raw material and gallium or germanium oxide molecular sieve catalyst particles are mixed evenly according to the mass ratio of 15:1, and added to the fluidized reactor;

(2) The sulfur gas after sulfur gasification of the reducing agent enters from the bottom of the fluidized reactor at a mass ratio of 8:1 to gypsum powder and a gas phase molar fraction of 60%, and contacts with the material in (1), at 680°C Decompose gypsum, the material residence time is 30min, and the gypsum decomposition rate is 95%.

(3), the solid phase obtained by the fluidized catalytic decomposition reaction (calcium sulfide mass fraction is 98% powder and catalyst particles) is steam washed, and the solid phase after washing is a metal oxide molecular sieve catalyst, after drying at 180 ° C Return to step (1) for recycling. The gas phase is first condensed to obtain a suspension with a mass fraction of calcium hydroxide of 50%, which can be reacted with carbon dioxide, nitric acid, phosphoric acid, hydrochloric acid, etc. to produce calcium salts such as calcium carbonate, calcium nitrate, calcium hydrogen phosphate, and calcium chloride. The uncondensed gas phase (with a hydrogen sulfide molar fraction of 96%) can be used alone or with the sulfur dioxide in the gas phase product after the fluidized catalytic decomposition reaction to produce sulfur by Claus reaction, and then returned to the system for recycling as a reducing agent.

(4), the 680 ℃ gaseous phase (the molar fraction of sulfur dioxide is 16%, the molar fraction of sulfur gas is 58%) that the fluidized catalytic decomposition reaction obtains is through dedusting, is cooled to 135 ℃, makes gaseous sulfur quench to be liquid sulfur, through Separation and preparation of insoluble sulfur with a purity ≥ 98.5%, while soluble sulfur is returned to the system as a reducing agent for recycling. The remaining gas phase (the molar fraction of sulfur dioxide is 12%) can be partially reacted with the hydrogen sulfide obtained after washing the solid phase product to produce sulfur and then returned to the system for recycling as a reducing agent, and the other part can be used to produce sulfuric acid.

Claims (4)

1. a method for fluid catalytic decomposing gypsum, is characterized in that: the concrete steps of described method are as follows:

(1), by powder gypsum raw material with metal oxide molecular sieve catalyst particle according to mass ratio (1 ~ 30): 1 mixes, and joins in fluidized reactor;

(2), reductive agent sulphur is by the mass ratio (2 ~ 10) with terra alba: 1, gas phase mole fraction 10% ~ 100%, enters bottom fluidized reactor, contacts with material in step (1), at 480 DEG C ~ 700 DEG C decomposing gypsums, residence time of material is at 1 ~ 60min;

(3), the solid phase that obtains of fluid catalytic decomposition reaction carries out steaming, and the solid phase after washing is metal oxide molecular sieve catalyst, returns step (1) and recycle after 120 DEG C ~ 200 DEG C dryings; And the first condensation of gas phase, obtain the suspension liquid that calcium hydroxide mass fraction is 20% ~ 60%, for the production of calcium salt; Uncooled gas phase retrieval system recycles as reductive agent;

(4), the gas phase of 480 DEG C ~ 700 DEG C that obtains of fluid catalytic decomposition reaction is through dedusting, be cooled to 120 DEG C ~ 150 DEG C, make gaseous state sulphur chilling be liquid-state sulfur, through being separated the insoluble sulfur of preparation purity >=98%, soluble sulfur then retrieval system recycles as reductive agent; The hydrogen sulfide obtained after remaining gas phase and solid product wash through claus reaction prepare sulphur again retrieval system recycle as reductive agent, or for the production of sulfuric acid.

2. the method for fluid catalytic decomposing gypsum as claimed in claim 1, it is characterized in that: in step (1), described gypsum raw material is the plaster of paris, one or more in anhydrite, phosphogypsum, desulfurated plaster, fluorgypsum, citric acid gypsum, nickel gypsum, bunt gypsum or titanium dioxide by-product gypsum.

3. the method for fluid catalytic decomposing gypsum as claimed in claim 1, it is characterized in that: in step (1), metal oxide component contained by described metal oxide molecular sieve catalyst is one or more in the oxide compound of scandium, titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, aluminium, gallium or germanium.

4. the method for fluid catalytic decomposing gypsum as claimed in claim 1, is characterized in that: the finished product are insoluble sulfur, at least one in sulfuric acid and calcium carbonate, nitrocalcite, secondary calcium phosphate, this several calcium salt of calcium chloride.